It sounds like you don’t have Unreal Engine plugins installed in VS. There should be some auto complete plugins, not sure if they’re free.
The best one that I’m aware of, you need to pay for. You can either buy RESharper as a VS plugin, or you can just use Rider as your IDE rather than VS, which has RESharper built in. Both are paid options.
Personally, having used JetBrains products in the past for other languages, I find VS’s interface to be clunky and slow, so I like Rider, which generally comes ready to plug and play with Unreal Engine. (If you use it, make sure to enable the Unreal Engine plugin during the install / first run setup).